Variable drive water line airboat

ABSTRACT

An airboat that may include an engine that is mounted to the hull of the airboat at an angle, and at least one propeller mounted to the hull of the airboat at an angle. The canted engine and propeller design may facilitate a lower center of gravity, a lower average center of thrust above the waterline, air induction for reduced surface drag, the lowering of torque roll forces, less overall boat height, and fuel efficiency with a reduced level of noise.

BACKGROUND OF THE INVENTION

The present invention relates to an improved airboat and, more particularly, to an airboat with a variable geometry hull and improved drive system.

An airboat, also known as a fanboat, is a flat-bottomed vessel propelled in a forward direction by an aircraft-type propeller and powered by either an aircraft or automotive engine. Airboats are a very popular means of transportation in the Florida Everglades, Frozen Arctic Tundra, Louisiana Bayous, where they are used for fishing, bow fishing, hunting and eco-tourism, and in other marshy and/or shallow/dry areas where a standard inboard or outboard engine with a submerged propeller would be impractical. Many airboat operations are limited by fuel efficiency, torque roll, high center of gravity, drag, overall height, propeller safety and noise.

As can be seen, there is a need for an improved airboat.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a airboat comprising; a hull comprising a substantially flat bottom; an engine mounted to the hull; and at least one propeller mounted to the hull near the rear of the hull, wherein the at least one propeller is operatively attached to the engine, wherein at least one of the engine and the at least one propeller is mounted at an angle relative to the substantially flat bottom of the hull.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the present invention;

FIG. 2 is a side section view of the present invention;

FIG. 3 is a view taken along line 3-3 in FIG. 2 illustrating propeller, gearbox and belts and demonstrating a method of rotation;

FIG. 4 is a perspective view of the present invention illustrating the propeller, gearbox and belts of FIG. 1;

FIG. 5 is a perspective view of the variable pitch propeller of FIG. 1 and illustrated in a pre-rotated configuration;

FIG. 6 is a perspective view of the variable pitch propeller of FIG. 1 and illustrated in a mid-rotated configuration;

FIG. 7 is a perspective view of the variable pitch propeller of FIG. 1 and illustrated in a post-rotated configuration;

FIG. 8 is a section detail view of the present invention along line 8-8 in FIG. 3;

FIG. 9 is a schematic view of the present invention demonstrating components related to the variable boat hull transom of FIG. 1 which is shown in pre-deployed configuration; and

FIG. 10: is a schematic view of the present invention demonstrating components related to the variable boat hull transom of FIG. 1 which is shown in post-deployed configuration.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

Broadly, an embodiment of the present invention provides an airboat that may include an engine that is mounted to the hull of the airboat at an angle, and at least one propeller mounted to the hull of the airboat at an angle. The canted engine and propeller design may facilitate a lower center of gravity, a lower average center of thrust above the waterline, air induction for reduced surface drag, the lowering of torque roll forces, less overall boat height, and fuel efficiency with a reduced level of noise.

The present invention may include an air propelled boat which may feature increased safety features, overall performance, noise reduction, and fuel economy. The present invention may include operator controlled variable pitch inter-leaved counter rotating twin propellers and variable boat hull shape features that may provide improved efficiency and safety for airboat propulsion and operation.

Referring to FIGS. 1 through 10, the present invention may include an airboat. The airboat may include a boat hull 10. In certain embodiments, the boat hull 10 may be built from welded aluminum. The boat hull 10 may include an engine 14 mounted to the inside. In certain embodiments, the engine 14 may be mounted at an angle relative to the bottom of the boat hull 10. The engine 14 may be an automobile engine 14. The engine 14 may be connected to the transmission comprising the gear box 16. The transmission may be clutch driven and may be a counter rotating transmission.

In certain embodiments, the gear box 16 may connect to and may be driven by the engine 14 via the engine input shaft 36. The gear box 16 may include gear box output sprockets 32 that may rotate. At least one propeller 18 may be mounted to the rear of the boat hull 10. The propeller 18 may be a variable tilt propeller. In certain embodiments, the variable pitch propellers 18 may be inter-leaved operator controlled variable pitch propellers 18. The at least one propeller 18 may include two propellers 18. The variable tilt propellers 18 may be mounted to the hull 10 at an angel relative to a substantially flat bottom of the hull 10.

The engine 14 may be connected to the propellers 18 and thereby rotate the propellers 18. As illustrated in the Figures, a belt 20 may connect a first sprocket 32 to a first propeller 28. Another belt 20 may connect a second sprocket 32 to a second variable tilt propeller 28. Thereby, when the engine 14 is turned on, the engine 14 rotates the first and second sprockets 32 and therefore rotates the first and second propellers 18. The propellers 18 may be within and protected by a housing that is connected to the back of the hull 10. The housing may be molded composite materials or metal.

The operator controlled variable pitch inter-leaved counter rotating twin propellers 18 may allow a low average push point, reduction of torque roll, and improved fuel performance features. This entire propeller system 18, and engine 14, may be placed at a canted angle and thus further reducing the average push point. The canted angle may reduce the average push point, thus increasing usable thrust as it is lower to the waterline. The canted angle may range from about a 10 degree angle to about an 80 degree angle relative to the hull bottom 10. For example, the angle may be between about 20 degrees to about 70 degrees, between about 30 degrees to about 60 degrees, or between about 40 degrees to about 50 degrees, such as 45 degrees. However, the operator controlled variable pitch inter-leaved counter rotating twin propellers 18 and the engine 14 may be mounted at different canted positions.

Thrust provided by the canted propeller 18 may be vectored through a variable hull transom 22. The variable hull transom 22 may be a retractable variable hull transom 22. As illustrated in FIGS. 9 and 10, the transom 22 may be connected to a pulley system which may include a pulley 36 and a rope 38. The pull system may further include a slide track 44 mounted to the hull 10. A slide track bracket 46 may slide up and down the slide track 44. The rope 38 may include a first end and a second end. The first end of the rope may attach to the transom 22 and the second end of the tope may connect to the slide track bracket 46. A spring 40 may include a first end attached to the slide bracket 46 and a second end attached to an anchor 42. When the spring 40 is compressed, the transom 22 may be in a closed position and when the spring 40 is extended the transom 22 may be in an open position. The transom 22 may be in an open position when the air boat is in use. The operator controllable transom 22 may be attached to the hull 10 which may act as a variable vectoring hull shape which also acts as a failsafe transom to keep water from entering the hull.

As illustrated in FIG. 2, the airflow 24 may be at least partially directed towards the water. In certain embodiments, the hull 10 of the present invention may further include an air escape port 26. A portion of the airflow 24 may be directed through the air escape port 26 which may be located at the bottom of the hull 10. The airflow 24 may exit the air escape port 26 through the bottom of the hull 10. This is to break surface viscous drag, thus reducing drag.

It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. 

What is claimed is:
 1. An airboat comprising; a hull comprising a substantially flat bottom, a front end and a rear end; an engine mounted to the hull; and at least one propeller mounted to the hull near the rear end of the hull, wherein the at least one propeller is operatively connected to the engine, wherein at least one of the engine and the at least one propeller is mounted at an angle relative to the substantially flat bottom of the hull.
 2. The airboat of claim 1, wherein the at least one propeller is two propellers mounted to the hull side by side.
 3. The airboat of claim 1, wherein the engine and the at least one propeller are mounted to the hull at an angle relative to the substantially flat bottom of the hull.
 4. The airboat of claim 1, further comprising a gear box operatively connected to the engine, wherein the gear box comprises at least one rotating sprocket attached to the at least one propeller via a belt.
 5. The airboat of claim 1, further comprising a retractable transom.
 6. The airboat of claim 5, wherein the retractable transom is operatively connected to an at least one of a pulley and spring system.
 7. The airboat of claim 5, wherein the pulley system comprises: a plurality of pulleys; a rope having a first end and a second end, wherein the first end is attached to the retractable transom, and wherein the rope is wrapped around the pulleys; a slide track mounted to the bottom of the hull; a slide bracket that slides along the slide track, wherein the second end of the rope is connected to the slide track; a spring having a first end and a second end, wherein the first end of the spring is attached to the slide bracket; and an anchor, wherein the second end of the spring is attached to the anchor.
 8. The airboat of claim 7, wherein the plurality of pulleys is three pulleys.
 9. The airboat of claim 1, wherein the angle is around 25 degrees relative to the flat bottom of the hull.
 10. The airboat of claim 1, further comprising an airflow escape port through the bottom of the hull, wherein at least a portion of airflow that is produced by the propellers is directed to the airflow escape port. 